Plate clamping mechanism



June 15, 1954 Filed June 14, 1951 c. A. HARLES S PLATE CLAMPING MECHANISM 4 Sheets-Sheet l Jime I5, 19 c. A. HARLESS PLATE CLAMPING MECHANISM Filed June 14, 1951 4 Sheets-Sheet 2 June 15, 1954 Filed June 14, 1951 c. A. HARLESS 2,681,007

PLATE CLAMPING MECHANISM 4 Sheets-Sheet '5 W I g 29 7 4 Sheets-Sheet '4 June 15, 1954 c. A. HHARLESS PLATE CLAMPING MECHANISM Filed June 14, 1951 Patented june 15,

UNITED STATES PLATE CLAMPING MECHANISM Charles A. Harless, Riverside, Conn, assignor to R. Hoe & Co., New York, N. Y., a corporation of New York Application June 14, 1951, Serial No. 231,590

7 Claims.

This invention relates to improvements in printing cylinder plate clamping mechanism.

It is an object of the invention to provide an improved. plate clamping mechanism for engaging under a stereotype or similar printing plate and holding the same on a printing cylinder.

Another object of the invention is to provide a clamping mechanism in which the clamp operating devices move the clamps in and out of the cylinder rapidly but operate slowly and accurately in applying the clamping pressure.

Still another object of the invention is to provide a clamping mechanism which is compact and easily adjusted.

With the foregoing objects as well as others which will appear in mind, the invention consists in the combinations and arrangements of parts and details of construction which will now first be fully described with reference to the accompanying drawing and then be more particularly pointed out in the appended claims.

In the drawing:

Figure 1 is a plan view of a printing cylinder embodying the invention in a preferred form, the plate being indicated in phantom;

Figure 2 is a section on the line 22 of Figure 1;

Figure 3 is an enlarged plan View of one of the clamping mechanisms of Figure 1, and. partly in section on the line 33 of Figure 6;

Figure 4 is a section on the line 4-4 of Figure 3 Figure 5 is a view similar to Figure 3, but showing the parts in a different position;

Figures 6 and 7 are sections on the respective lines 6% and 'i'l of Figure 3;

Figure 8 is a section similar to Figure 7, but showing the parts in a difierent position (corresponding to the portion of parts in Figure 5) Figure 9 is a section on the line 99 of Figure 3;

Figure 10 is a plan view partly broken away, showing a modified form of clamping mechanism; and

Figure 11 is a section on the line I ll I of Figure 10.

The cylinder 1 is carried on a shaft 2, as usual, and may accommodate eight semi-cylindrical plates. Figure 1 shows the cylinder structure to the left of the central clamp bar 3, it being understood that this structure is duplicated to the right of the bar, generally with a displacement through a right angle to stagger the plates and reduce vibration.

Each half of the cylinder is provided with eight clamping mechanisms 4, four of which are shown in Figure 1 and the other four of which are symmetrically placed on the opposite side of the cylinder.

Axially slidable rods 5 serve to operate the clamping mechanisms 4, as well as the curved edge clamps 6, these rods being moved as required and held in required position by the clamp operating sectors 1. This part of the structure may be the same as shown in application Serial No. 58,202, filed November 4, 1948, now Patent No. 2,590,010, for Plate Clamping Mechanism, and will not be further described herein. It is suificient for purposes of the present invention to note that the mechanism is capable of sliding the rods 5 between, and holding the rods 5 in, a clamping position and a releasing position.

The curved end clamps 6 are urged by springs 8 against the end plates which, in turn, urge intermediate slidable curved end clamps 9 against the inner plates and thus urge these plates against the center clamp bar 3. The arrangements for moving and releasing these parts in proper sequence are well known and will not be described herein.

Each clamping mechanism 4 includes a frame structure 10 accommodated in a suitable recess in the cylinder 1 and held therein by means of screws H. The operating rod 5 terminates short of the first clamping mechanism 4 and is connected by means of a block l2 to a plate !3 slidable in a groove below the frame It (Figures 4 and 5). Beyond the clamping mechanism 4 a second rod 5', for operating the next clamping mechanism, is similarly attached to plate l3 by means of a similar block 12. Sliding plate l3 has a transversely extending slot I5 for operating the clamps as described .below.

The hooks or clamps proper i6 operate in cut outs in the member 10 (Figure 8) and are carried by a block ll, supported by trunnion pins i8 piv-- otally carried by links 19, which, in turn, are pivotally supported on pins 29 in the frame member I0, the links or arms 19 are arranged in a parallelogram and support the block ii for parallel movement. The hooks I6 thus move outwardly as well as circumferentially in going from the retracted position of Figure 8 to the protracted or clamping position of Figure '7. An axially extending slot 2i (Figure 3) in the block ll accommodates a roller 22 rotatably mounted on a generally radial crank pin 23 (Figure 4) which also carries a rotatable roller 24 within the transverse slot IS in the axially slidable member l3. Crank pin 23 is carried by the crank arm 25 (Figure 5) on which is also formed a short crank shaft 26 journalled in a bore 27 (Figure 6) in a bracket member 28. Above the shaft 25, the crank arm 25 has a cylindrical hub 29 seating in a cylindrical seat 36 of the member 28 for taking the thrust on the arm. The bracket member 28 is held in position by a pair of screws 3i (Figure 9) threadably engaged in it and thrusting against a wall 32 of the recess in the cylinder. These screws have heads 33 which abut an opposite wall 32 of the recess. The screw heads 33 have axially extending hexagonal sockets 3% to take an L-shaped wrench and depressions 35 cooperating with a spring pressed plunger 36. The position of member 28 may be adjusted by inserting the wrench in the socket 3-; and turning the screw to the required extent, the screw being held in adjusted position by the plunger 3%.

Starting with the parts in retracted position, a movement of the rod 5 (to the right in the Figures 4 and 5) will cause the arm 25 to swing counterclockwise about the axis of the crank shaft 28 from the position of Figure 5 toward that of Figure 3, by reason of the engagement of roller 2 1 in the transverse slot 55. At the same time roller 22 acting in axial slot 2i in the block ll which carries the clamps, will force this element from the retracted position of Figures 5 and 8 to the clamping position of Figures 3 and 7. With the arm 25 at approximately 45 in retracted position, as indicated in Figure 5, the initial 0 movement of the clamps will be substantially equal to the movement of the bar 5, furnishing a rapid movement of the clamps toward locking position. However, as the arm 25 approaches a position at right angles to the slot 2!, a given movement of the bar 5 produces only a very small movement of the clamps, resulting in a high mechanical advantage and a very accurately controllable clamping action. While the clamps are rapidly protracted above the cylinder surface, their movement may be substantially circumferential when the final clamping pressure is actually applied or may even be slightly inward, if desired.

The usual stops 37 (Figure 3) may be utilized,

being accommodated by suitable grooves in the cylinder, which are enlarged as at 38 to permit operation of the screws 3! by an L-shaped wrench. Normally the clamping mechanism t will be adjusted so as to bring one end of the plate up against the stop 3'! to properly position it, the other end being spaced somewhat from the corresponding stop at the other end of the plate. All plates may be urged clockwise against the stops 3?- at one end of the plate or oounterclockwise against the stops at the other end of the plate, depending on the direction of rotation of the cylinder so that the clamping mechanism may be utilized for reversible printing units.

Where adjustable stops are desired, provision may readily be made for them and a modified construction in which such provision is mad is 'lustrated in Figures 10 and 11. The clamping mechanism generally is the same as previously described. The stops 3'5 are, however, eliminated, and stop members it are substituted. Screws ii are threadably engaged in this member and abut against the frame member 58 as shown. The heads of the screws are bored as at 26 to receive a pin wrench and also to be engaged by a button it secured on a fiat spring E5, which retains the screw in adjusted position. Upwardly extending projections ll serve as stops for the edge of the plate, the member 49 generally being depressed as indicated, so as to slide under the frame l0 and being cut out as at 48 so as not to interfere with the frame member it. Bores 49 through the member 40 accommodate the screws 3i previously referred to.

While the cylinder of the invention has been shown as equipped with a complete set of curved edge clamps 6 for the plates, there being four such clamps in engagement with each plate, the four clamps near the corners of the plates will ordinarily be found unnecessary and may be omitted. In certain cases, the curved edg clamps may be omitted entirely, but it is preferrad to utilize two such clamps to avoid possible flying off of a plate should it break loose from the clamps underneath it.

What is claimed is:

1. In a pri ting cylinder, plate clamping mech anism comprising a member having an axially extending slot and carrying a clamp for engaging circumferentially under a plate to hold the same on the cylinder, pivoted arms arranged in a parallelogram and supporting said member for parallel movement to and from a clamping position in which the clamp protrudes out beyond the cylinder surface and a retracted position in which the clamp is below the cylinder surface, a crank having a pin in the said slot for moving the clamp member, the pin and slot being relatively movable axially of the pin, and means for operating the crank.

2. In a printing cylinder, plate clamping mechanism comprising a member having an axially extending slot and carrying a clamp for engaging under a plate to hold the same on the cylinder, pivoted arms arranged in a parallelogram and supporting said member for parallel movement to and from a clamping position in which the clamp protrudes out beyond the cylinder surface and a retracted position in which the clamp is below the cylinder surface, a crank having a pin in the said slot for moving the clamp member, and means for operating the crank, the pin and slot being relatively movable axially of the pin and the crank being at substantially a right angle to the slot when the clamp member is in clamping position.

3. In a printing cylinder, plate clamping mechanism comprising a member having an axially extending slot and carrying a clamp for engaging circumferentially under a plate to hold the same on the cylinder, pivoted arms arranged in a parallelogram and supporting said member for parallel movement to and from clamping position, an axially slidable operating member having a transverse slot crossing the first said slot, and a crank having a pin in the said slots for movement by the operating member and moving the clamp member.

4. In a printing cylinder, plate clamping mech" anism comprising a member having an axially extending slot and carrying a clamp for engaging under a plate to hold the same on the cylinder, pivoted arms arranged in a parallelogram and supporting said member for parallel movement to and from a clamping position in which the clamp protrudes out beyond the cylinder surface and a retracted position in which the clamp is below the cylinder surface, a crank having a pin in the said slot for moving the clamp member, means for operating the crank, and a circumferentially ad justable mounting for the crank shaft.

5. In a printing cylinder, plate clamping mechanism comprising a member having an axially extending slot and carrying a clamp for engaging circumferentially under a plate to hold the same on the cylinder, pivoted arms arranged in a parallelogram and supporting said member for par allei movement to and from clamping position, an axially slidable operating member having a transverse slot crossing the first said slot, a crank having a pin in the said slots for movement by the operating member and moving the clamp member, and an adjustable mounting for the 6. In aprinting cylinder, plate clamping mechanism comprising a member having an axially extending slot and carrying a clamp for engaging under a plate to hold the same on the cylinder, means supporting said member for circumferential movement to and from clamping position, a crank having a pin in the said slot for moving the clamp member, and an axially slidable memoer having a transverse slot also engaging around the pin for operating the crank.

7. in a printing cylinder, plate clamping mech anism comprising a member having an axially extending slot and carrying a clamp for engaging under a plate to hold the same on the cyiinder, means supporting said member for circumferential movement to and from clamping position, a crank having a pin in the said slot for moving the clamp member, an axially slidable member having a. transverse slot also engaging around the pin for operating the crank, and an adjustable mounting for the crank.

Referenees Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,073,705 Petri-Palmedo Sept. 23, 1913 1,831,219 Wood Nov. 10, 1931 2,072,909 Stephenson Mar. 9, 1937 

